draft CAOM-to-ObsCore mapping

CAOM-ObsCore-mapping.md

@@ -0,0 +1,110 @@
+# CAOM - ObsCore Mapping
+
+This is the standard mapping between CAOM-2.5 and ObsCore-1.2 - both at working draft (WD) stage.
+
+Informative: the standard CAOM table and column names are included below; these will be specified
+in a separate standard (CAOM-TAP). The standard rules to generate the relational mapping:
+* {model prefix} -> {schema name}
+* {entity class name} -> {table name}
+* {vodml-id} -> (dots converted to underscore) -> {column_name} (vodml-id rules TBD)
+
+|CAOM vodml-id|CAOM table|CAOM column|ObsCore table/view|ObsCore column|
+|-------------|----------|-----------|------------------|--------------|
+|Observation.uri|caom2.Observation|uri|ivoa.ObsCore|obs_id|
+|Observation.collection|caom2.Observation|collection|ivoa.ObsCore|obs_collection|
+|Telescope.name|caom2.Observation|telescope_name|ivoa.ObsCore|facility_name|
+|Instrument.name|caom2.Observation|instrument_name|ivoa.ObsCore|instrument_name|
+|Target.name|caom2.Observation|target_name|ivoa.ObsCore|target_name|
+|Plane.uri|caom2.Plane|uri|ivoa.ObsCore|obs_creator_did|
+||caom2.Plane|publisherID|ivoa.ObsCore|obs_publisher_did|
+|Plane.dataRelease|caom2.Plane|dataRelease|ivoa.ObsCore|obs_release_date|
+|Plane.dataProductType|caom2.Plane|dataProductType|ivoa.ObsCore|dataproduct_type|
+|Plane.calibrationLevel|caom2.Plane|calibrationLevel|ivoa.ObsCore|calib_level|
+||||ivoa.ObsCore|access_url|
+||||ivoa.ObsCore|access_format|
+||||ivoa.ObsCore|access_estsize|
+|||||||
+|Position.bounds|caom2.Plane|position_bounds|ivoa.ObsCore|s_region|
+|--|caom2.Plane|_function_|ivoa.ObsCore|s_ra|
+|--|caom2.Plane|_function_|ivoa.ObsCore|s_dec|
+|--|caom2.Plane|_function_|ivoa.ObsCore|s_fov|
+|Position.minBounds|caom2.Plane|position_minBounds|||
+|--|caom2.Plane|_function_|ivoa.ObsCore|s_fov_min|
+|Position.resolution|caom2.Plane|position_resolution|ivoa.ObsCore|s_resolution|
+|Position.resolutionBounds|caom2.Plane|position_resolutionBounds|||
+|--|caom2.Plane|_function_|ivoa.ObsCore|s_resolution_min|
+|--|caom2.Plane|_function_|ivoa.ObsCore|s_resolution_max|
+|Position.dimension|caom2.Plane|position_dimension|||
+|--|caom2.Plane|_function_|ivoa.ObsCore|s_xel1|
+|--|caom2.Plane|_function_|ivoa.ObsCore|s_xel2|
+|||||||
+|Energy.bounds|caom2.Plane|energy_bounds|||
+|--|caom2.Plane|_function_|ivoa.ObsCore|em_min|
+|--|caom2.Plane|_function_|ivoa.ObsCore|em_max|
+|Energy.resolvingPower|caom2.Plane|energy_resolvingPower|ivoa.ObsCore|em_res_power|
+|Energy.resolution|caom2.Plane||ivoa.ObsCore|em_resolution|
+|Energy.resolutionBounds|caom2.Plane|energy_resolutionBounds|||
+|--|caom2.Plane|_function_|ivoa.ObsCore|em_resolution_min|
+|--|caom2.Plane|_function_|ivoa.ObsCore|em_resolution_max|
+|Energy.dimension|caom2.Plane|energy_dimension|ivoa.ObsCore|em_xel|
+|||||||
+|Time.bounds|caom2.Plane|time_bounds|ivoa.ObsCore||
+|--|caom2.Plane|_function_|ivoa.ObsCore|t_min|
+|--|caom2.Plane|_function_|ivoa.ObsCore|t_max|
+|Time.exposure|caom2.Plane|time_exposure|ivoa.ObsCore|t_exptime|
+|Time.exposureBounds|caom2.Plane|time_exposureBounds|||
+|--|caom2.Plane|_function_|ivoa.ObsCore|t_exptime_min|
+|--|caom2.Plane|_function_|ivoa.ObsCore|t_exptime_max|
+|Time.resolution|caom2.Plane|time_resolution|ivoa.ObsCore|t_resolution|
+|Time.dimension|caom2.Plane|time_dimension|ivoa.ObsCore|t_xel|
+|||||||
+|Polarization.states|caom2.Plane|polarization_states|ivoa.ObsCore|pol_states|
+|Polarization.dimension|caom2.Plane|polarization_dimension|ivoa.ObsCore|pol_xel|
+|Observable.ucd|caom2.Plane|observable_ucd|ivoa.ObsCore|o_ucd|
+|||||||
+|Position.maxRecoverableScale|caom2.Plane|position_maxRecoverableScale|||
+|--|caom2.Plane|_function_|ivoa.ObsCore_radio|s_largest_angular_scale_min|
+|--|caom2.Plane|_function_|ivoa.ObsCore_radio|s_largest_angular_scale_max|
+|Visibility.distance|caom2.Plane|uv_distance|||
+|--|caom2.Plane|_function_|ivoa.ObsCore_radio|uv_distance_min|
+|--|caom2.Plane|_function_|ivoa.ObsCore_radio|uv_distance_max|
+|Visibility.distributionEccentricity|caom2.Plane|uv_distributionEccentricity|ivoa.ObsCore_radio|uv_distribution_ecc|
+|Visibility.distributionFill|caom2.Plane|uv_distributionFill|ivoa.ObsCore_radio|uv_distribution_fill|
+
+## Observation.uri
+This identifier is used as values are also used in DerivedObservation.members (references). Two forms are supported:
+* caom:{collection}/{observation identifier}
+* ivo://{authority}/{collection}?{observation identifier}
+
+Unless there is a reason to resolve such identifiers via an IVOA registry lookup of the collection, the `caom` 
+form is recommended. Implementation detail: it is also used to put/get/update/delete observations via the metadata API.
+
+## Plane.uri
+This identifier is as values are also used in Provenance.inputs (references). Two forms are supported:
+* caom:{collection}/{plane identifier}
+* ivo://{authority}/{collection}?{plane identifier}
+
+This value is the _creator dataset identifer_ in normal IVOA usage. Implementation detail: the metadata API normally 
+copies this value and uses it as the `publisherID`; metadata sync tools (to mirror metadata) transform this value into
+a suitable local `publisherID` value (see below).
+
+## publisherID
+The `publisherID` field **is not** strictly part of the model because it must be modified when metadata instances are
+synchronised (mirrored) by different data centres (publisher). Exclusion from the model means the `publisherID` is not
+included in the mataChecksum calculation. This field is part of a correct implementation since this value is required 
+in ObsCore and (will be required) CAOM-TAP.
+
+## function
+Where the `vodml-uid` is `--` and the CAOM column is _function_, this is a continuation of the preceding line and
+means that the ObsCore scalar value is extracted from the non-scalar CAOM value. For example, to map
+`{s_region,s_ra,s_dec,s_fov}` from ObsCore to CAOM, one only needs to map the value of `s_region` to `position_bounds`;
+all the other values are computed from the `position_bounds`.
+
+## access
+Access to data from CAOM involves querying for the Artifact(s) that belong to a Plane and resolving the `Artiafct.uri`
+to a data access mechanism (URL or other); this is normally done by calling a DataLink service with the `caom2.Plane.publisherID` or `ivoa.ObsCore.obs_publisher_did` value and the DataLink service performs the query and
+resolution (dependent on storage APIs). The `access` fields in `ivoa.ObsCore` are generated on query output and can be
+either:
+1. a generated link to the appropriate DataLink service with the publisherID included
+2. a generated link to a service that can package multiple files in a single download (e.g. tar or zip download)
+Option 1 is the preferred solution.

build.gradle

@@ -9,7 +9,7 @@ repositories {
     mavenLocal()
 }
 
-sourceCompatibility = 1.8
+sourceCompatibility = 11
 
 group = 'org.opencadc'
 
@@ -49,9 +49,9 @@ xslt {
 }
 
 dependencies {
-    testCompile 'org.opencadc:cadc-vodml:[1.0.9,1.1)'
-
-    testCompile 'junit:junit:4.13' 
+    testImplementation 'org.opencadc:cadc-util:[1.12.5,)'
+    testImplementation 'org.opencadc:cadc-vodml:[1.0.9,1.1)'
+    testImplementation 'junit:junit:4.13' 
 }
 
 apply from: 'opencadc.gradle'